It is conventional to mount a shaft for rotation on anti-friction bearings in which an inner bearing race, fixed to the shaft, rotates with the shaft, while an outer race is fixedly mounted to the housing and wherein ball bearings or other anti-friction bearing members are interposed between the two races. Such bearing structure is sufficient to properly maintain the shaft in rotation about its axis supported by the fixed housing and with a very low friction loss as a result of such mounting. Unfortunately, such bearing structures do provide sufficient sealability. Attempts have been made to provide pressure seals to one or both sides of the anti-friction bearing and between the fixed housing and the rotating shaft. Such rotary shaft seals to date have been complex, costly, and the seal integrity is difficult to maintain, particularly where relatively high pressures are exerted on the seal element maintaining a contact interface between the rotary and stationary elements of this type of seal. Where the fluids acting on the seal constitute liquids including abrasives and the like, the abrasion contact tends to destroy the seal or at least impair its integrity.
It is, therefore, an object of the present invention to provide an improved rotary shaft seal which is designed to meet requirements for specified dimension and materials in a wide variety of industry applications and which is applicable to gritty liquids, sewage, sludge, corrosive and abrasive and other problem fluids and which prevents the sludge and grit from working into the seal to destroy or collapse the interior mechanism.
It is a further object of this invention to provide an improved rotary seal which is simple in design and assembly, insures reliable performance, and which uses the pressure of the fluid acting on the seal to maintain the very integrity of the seal.
It is a further object of the invention to provide an improved rotary seal which eliminates the use of flushing sea water, grease cup, sealing liquid, springs, screws, and requires no internal or external adjustment, and in which installation is easily achieved without the requirement of special tools.